Impact modified polycarbonate compositions

ABSTRACT

The present invention relates to non-aging, impact-modified polycarbonate compositions and molding compositions comprising: A) from 60 to 86 parts by weight (based on the sum of components A+B+C) of aromatic polycarbonate and/or aromatic polyester carbonate, B) from 4 to 12 parts by weight (based on the sum of components A+B+C) of graft polymer comprising: B.1 from 10 to 50 wt. % (based on the graft polymer B) of a shell of at least one vinyl monomer, and B.2 from 90 to 50 wt. % (based on the graft polymer B) of a graft base of silicone-acrylate composite rubber, C) from 10 to 30 parts by weight (based on the sum of components A+B+C) of a polymer or copolymer based on vinyl monomer, and D) from 0 to 20 parts by weight of polymer additives.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of U.S. patent application Ser. No.12/484,388 filed Jun. 15, 2009 now U.S. Pat. No. 8,338,533, which claimspriority to DE 102008028571.4 filed Jun. 16, 2008, the entire contentsof each are herein incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to non-aging, impact-modifiedpolycarbonate compositions and moulding compositions which aredistinguished by an improved balance of multiaxial low-temperatureimpact strength and flowability, good dyeability and a high heatdistortion resistance.

2. Description of Related Art

Compositions comprising polycarbonate, graft polymer based onrubbery-elastic, non-aging graft base and vinyl aromatic copolymer areknown in principle.

DE-A 4434965, for example, discloses such compositions that have animproved balance of low-temperature strength, rigidity and flowbehaviour and that comprise polycarbonate (A), graft polymer withrubbery-elastic graft bases having a specific particle size (B) andthermoplastic vinyl aromatic (co)polymer (C), wherein the relativeproportions B to C are limited. Silicone-acrylate composite rubbers arenot disclosed as the rubbery-elastic graft base in this application.

EP-A 0537014 discloses compositions having improved low-temperaturestrength that comprise a thermoplastic resin, for example apolycarbonate, a vinyl polymer or a mixture thereof, and animpact-modifying amount of a specific multiphase graft polymer based onpolyorganosiloxane/polyvinyl. Compositions comprising polycarbonate,vinyl polymer and graft polymer in which the vinyl polymer and the graftpolymer are used in specific relative proportions are not disclosed.

EP-A 0486853 discloses compositions having improved dyeability throughthe use of pigments comprising a specific graft polymer based on apolyorganosiloxane-polyalkyl (meth)acrylate compound rubber andoptionally further thermoplastics such as, for example, polycarbonate.

EP-A 0430134 discloses compositions that have excellent impact strength,surface hardness and surface quality and that comprise polycarbonate anda specific polyorganosiloxane graft polymer based on a composite rubberas graft base, which comprises from 1 to 10 wt. % polyorganosiloxanerubber and from 99 to 90 wt. % polyalkyl (meth)acrylate rubber innon-separable form. It is disclosed that the compositions canadditionally also contain homopolymers or copolymers based on vinylmonomers. There is no mention in this application of particularadvantages that can be achieved in terms of properties when the threecomponents are used in the specific mixing ratio.

EP-A 0307963 discloses compositions that have good resistance tochemicals, to weathering and to heat as well as good impact strength andthat comprise polycarbonate, graft polymer based on a silicone-butylacrylate composite rubber base and vinyl copolymer. However, thedisclosed compositions exhibit a disadvantageous ratio of graft polymercontent to vinyl copolymer content. The dyeing of such compositions indark and brilliant colours requires large amounts of pigments, whichresult in a deterioration of the mechanical properties of thecomposition.

EP-A 1334153 discloses compositions that have improved stability to heataging, a high surface quality and good processability and that comprisepolycarbonate, graft polymer based on silicone-acrylate compositerubber, vinyl copolymer and mineral filler (glass fibres). Thesecompositions have a strength that is inadequate for many applications—inparticular at low temperatures.

SUMMARY OF THE INVENTION

An object of the present invention was to provide non-agingpolycarbonate compositions and moulding compositions which aredistinguished by an improved balance of multiaxial low-temperaturestrength and melt flowability, by good dyeability and by a high heatdistortion resistance.

A particular object of the present invention was to provide non-agingpolycarbonate compositions, which can be dyed even in dark and brilliantcolours, for example for use as unlacquered automotive interiorcomponents and automotive bodywork parts, which do not exhibitsplintering fracture down to −10° C. in application-relevant ductilitytests, have a melt viscosity, measured at 260° C. and a shear rate of1000 s⁻¹, of not more than 250 Pas and a heat distortion resistance,measured as Vicat B120, of at least 125° C.

It has been found, surprisingly, that the desired property profile canbe exhibited by a composition comprising

A) from 60 to 86 parts by weight, preferably from 65 to 80 parts byweight, particularly preferably from 70 to 80 parts by weight (based onthe sum of components A+B+C) of aromatic polycarbonate and/or aromaticpolyester carbonate,

B) from 4 to 12 parts by weight, preferably from 5 to 10 parts byweight, particularly preferably from 6 to 10 parts by weight (based onthe sum of components A+B+C) of graft polymer comprising

B.1 from 10 to 50 wt. %, preferably from 20 to 40 wt. % (in each casebased on the graft polymer B) of a shell of at least one vinyl monomerand

B.2 from 90 to 50 wt. %, preferably from 80 to 60 wt. % (in each casebased on the graft polymer B) of one or more graft bases ofsilicone-acrylate composite rubber,

C) from 10 to 30 parts by weight, preferably from 12 to 25 parts byweight, particularly preferably from 14 to 20 parts by weight (based onthe sum of components A+B+C) of a polymer or copolymer based on vinylmonomer, and

D) from 0 to 20 parts by weight, preferably from 0.1 to 10 parts byweight, particularly preferably from 0.2 to 5 parts by weight (based onthe sum of components A+B+C) of polymer additives,

wherein components B and C are present in a ratio of the parts by weightof B:C in the range from 1:1.3 to 1:3.5, preferably in the range from1:1.5 to 1:3.0, particularly preferably in the range from 1:1.6 to1:2.7,

wherein the composition is free of inorganic fillers, and

wherein all parts by weight in the present application are so normalisedthat the sum of the parts by weight of components A+B+C in thecomposition is 100.

Additional objects, features and advantages of the invention will be setforth in the description which follows, and in part, will be obviousfrom the description, or may be learned by practice of the invention.Objects, features and advantages of the invention may be realized andobtained by means of the instrumentalities and combination particularlypointed out in the appended claims.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Component A

Aromatic polycarbonates and/or aromatic polyester carbonates accordingto component A that are suitable according to the invention are known inthe literature or can be prepared by processes known in the literature(for the preparation of aromatic polycarbonates see, for example,Schnell, “Chemistry and Physics of Polycarbonates”, IntersciencePublishers, 1964 and DE-AS 1 495 626, DE-A 2 232 877, DE-A 2 703 376,DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the preparation ofaromatic polyester carbonates see e.g. DE-A 3 077 934).

The preparation of aromatic polycarbonates can be carried out, forexample, by reaction of diphenols with carbonic acid halides, preferablyphosgene, and/or with aromatic dicarboxylic acid dihalides, preferablybenzenedicarboxylic acid dihalides, according to the interfacialprocess, optionally using chain terminators, for example monophenols,and optionally using branching agents having a functionality of three ormore than three, for example triphenols or tetraphenols. Preparation bya melt polymerisation process by reaction of diphenols with, forexample, diphenyl carbonate is also possible.

Diphenols for the preparation of the aromatic polycarbonates and/oraromatic polyester carbonates include preferably those of formula (I)

whereinA is a single bond, C₁- to C₅-alkylene, C₂- to C₅-alkylidene, C₅- toC₆-cycloalkylidene, —O—, —SO—, —CO—, —S—, —SO₂—, C₆- to C₁₂-arylene, towhich further aromatic rings optionally containing heteroatoms can befused,or a radical of formula (II) or (III)

B is in each case C₁- to C₁₂-alkyl, preferably methyl, halogen,preferably chlorine and/or bromine,x each independently of the other is 0, 1 or 2,p is 1 or 0, andR⁵ and R⁶ can be chosen individually for each X¹ and each independentlyof the other is hydrogen or C₁- to C₆-alkyl, preferably hydrogen, methylor ethyl,X¹ is carbon andm is an integer from 4 to 7, preferably 4 or 5, with the proviso that onat least one atom X¹, R⁵ and R⁶ are simultaneously alkyl.

Preferred diphenols include hydroquinone, resorcinol,dihydroxydiphenols, bis-(hydroxyphenyl)-C₁-C₅-alkanes,bis-(hydroxyphenyl)-C₅-C₆-cycloalkanes, bis-(hydroxyphenyl) ethers,bis-(hydroxyphenyl) sulfoxides, bis-(hydroxyphenyl) ketones,bis-(hydroxyphenyl)-sulfones andα,α-bis-(hydroxyphenyl)-diisopropyl-benzenes, and derivatives thereofbrominated and/or chlorinated on the ring.

Particularly preferred diphenols include 4,4′-dihydroxydiphenyl,bisphenol A, 2,4-bis(4-hydroxyphenyl)-2-methylbutane,1,1-bis-(4-hydroxyphenyl)-cyclohexane,1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenylsulfone and di-and tetra-brominated or chlorinated derivatives thereof such as, forexample, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane,2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane or2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane,2,2-Bis-(4-hydroxyphenyl)-propane (bisphenol A) is particularlypreferred.

The diphenols can be used on their own and/or in the form of arbitrarymixtures. The diphenols are known in the literature or are obtainableaccording to processes known to one of skill in art in the literature.

Chain terminators suitable for the preparation of thermoplastic aromaticpolycarbonates include, for example, phenol, p-chlorophenol,p-tert-butylphenol or 2,4,6-tribromophenol but also long-chainedalkylphenols, such as 4-[2,4,4-trimethylpentyl)]-phenol,4-(1,3-tetramethylbutyl)-phenol according to DE-A 2 842 005 ormonoalkylphenol or dialkylphenols having a total of from 8 to 20 carbonatoms in the alkyl substituents, such as 3,5-di-tert-butylphenol,p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol and2-(3,5-dimethylheptyl)-phenol and 4-(3,5-dimethylheptyl)-phenol. Theamount of chain terminators to be used is generally from 0.5 mol % to 10mol %, based on the molar sum of the diphenols used in a particularcase.

The thermoplastic aromatic polycarbonates can be branched in a knownmanner, preferably by the incorporation of from 0.05 to 2.0 mol %, basedon the sum of the diphenols used, of compounds advantageously having afunctionality of three or more than three, for example those havingthree or more phenolic groups.

Both homopolycarbonates and copolycarbonates are suitable. For thepreparation of copolycarbonates of component A according to the presentinvention, it is also possible to use from 1 to 25 wt. %, preferablyfrom 2.5 to 25 wt. %, based on the total amount of diphenols to be used,of polydiorganosiloxanes having hydroxyaryloxy end groups. These areknown (U.S. Pat. No. 3,419,634) and can be prepared according toprocesses known in the literature. The preparation of copolycarbonatescontaining polydiorganosiloxanes is described in DE-A 3 334 782.

Preferred polycarbonates in addition to the bisphenol Ahomopolycarbonates include the copolycarbonates of bisphenol A,advantageously with up to 15 mol %, based on the molar sums ofdiphenols, of diphenols other than those mentioned as being preferred orparticularly preferred, in particular2,2-bis(3,5-dibromo-4-hydroxyphenyl)-propane.

Aromatic dicarboxylic acid dihalides for the preparation of aromaticpolyester carbonates can preferably be diacid dichlorides of isophthalicacid, terephthalic acid, diphenyl ether 4,4′-dicarboxylic acid andnaphthalene-2,6-dicarboxylic acid.

Mixtures of the diacid dichlorides of isophthalic acid and terephthalicacid in a ratio of from 1:20 to 20:1 are particularly preferred.

In the preparation of polyester carbonates, a carbonic acid halide,preferably phosgene, is additionally used concomitantly as abifunctional acid derivative.

Suitable chain terminators for the preparation of the aromatic polyestercarbonates, in addition to the monophenols already mentioned, alsoinclude chlorocarbonic acid esters thereof and the acid chlorides ofaromatic monocarboxylic acids, which can optionally be substituted byC₁- to C₂₂-alkyl groups or by halogen atoms, as well as aliphatic C₂- toC₂₂-monocarboxylic acid chlorides.

The amount of chain terminators is advantageously in each case from 0.1to 10 mol %, based in the case of phenolic chain terminators on moles ofdiphenol and in the case of monocarboxylic acid chloride chainterminators on moles of dicarboxylic acid dichloride.

The aromatic polyester carbonates can also optionally contain aromatichydroxycarboxylic acids incorporated therein.

The aromatic polyester carbonates can be both linear and/or branched inany known manner (see in this connection DE-A 2 940 024 and DE-A 3 007934).

There can optionally be used as branching agents, for example,carboxylic acid chlorides having a functionality of three or more, suchas trimesic acid trichloride, cyanuric acid trichloride,3,3′-,4,4′-benzophenone-tetracarboxylic acid tetrachloride,1,4,5,8-naphthalenetetracarboxylic acid tetrachloride or pyromelliticacid tetrachloride, in amounts of from 0.01 to 1.0 mol % (based ondicarboxylic acid dichlorides used), or phenols having a functionalityof three or more, such as phloroglucinol,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-hept-2-ene,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane,1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane,tri-(4-hydroxyphenyl)-phenylmethane,2,2-bis[4,4-bis(4-hydroxy-phenyl)-cyclohexyl]-propane,2,4-bis(4-hydroxyphenyl-isopropyl)-phenol,tetra-(4-hydroxyphenyl)-methane,2,6-bis(2-hydroxy-5-methyl-benzyl)-4-methyl-phenol,2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)-propane,tetra-(4-[4-hydroxyphenyl-isopropyl]-phenoxy)-methane,1,4-bis[4,4′-dihydroxytriphenyl)-methyl]-benzene, in amounts of from0.01 to 1.0 mol %, based on diphenols used. Phenolic branching agentscan be placed in a vessel with the diphenols; acid chloride branchingagents can be introduced together with the acid dichlorides if desiredfor any reason.

The content of carbonate structural units in the thermoplastic aromaticpolyester carbonates can vary as desired. The content of carbonategroups is preferably up to 100 mol %, in particular up to 80 mol %,particularly preferably up to 50 mol %, based on the sum of ester groupsand carbonate groups. Both the esters and the carbonates contained inthe aromatic polyester carbonates can be present in the polycondensationproduct in the form of blocks and/or distributed randomly.

In a preferred embodiment of the present invention, the aromaticpolycarbonates and aromatic polyester carbonates advantageously have aweight-average molecular weight (M_(w), measured, for example, by GPC,ultracentrifugation or scattered light measurement) of from 22,000 to32,000 g/mol, particularly preferably from 24,000 to 28,000 g/mol.

The thermoplastic aromatic polycarbonates and polyester carbonates canbe used on their own and/or in an arbitrary mixture.

Component B

The graft copolymers B can generally be prepared by radicalpolymerisation, for example by emulsion, suspension, solution or masspolymerisation, preferably by emulsion polymerisation.

Suitable monomers B.1 include vinyl monomers such as vinyl aromaticcompounds and/or vinyl aromatic compounds substituted on the ring (suchas styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene),methacrylic acid (C₁-C₈)-alkyl esters (such as methyl methacrylate,ethyl methacrylate, 2-ethylhexyl methacrylate, allyl methacrylate),acrylic acid (C₁-C₈)-alkyl esters (such as methyl acrylate, ethylacrylate, n-butyl acrylate, tert-butyl acrylate), organic acids (such asacrylic acid, methacrylic acid) and/or vinyl cyanides (such asacrylonitrile and methacrylonitrile) and/or derivatives (such asanhydrides and imides) of unsaturated carboxylic acids (for examplemaleic anhydride and N-phenyl-maleimide). These vinyl monomers can beused on their own or in mixtures of at least two monomers.

Preferred monomers B.1 can be selected from at least one of the monomersstyrene, methyl methacrylate, n-butyl acrylate and acrylonitrile.Particular preference is given to the use of methyl methacrylate or amixture of styrene and acrylonitrile as the monomer B.1.

The glass transition temperature of the graft base B.2 is typically <10°C., preferably <0° C., particularly preferably <−20° C. The graft baseB.2 generally has a mean particle size (d50 value) of from 0.05 to 10μm, preferably from 0.06 to 5 μm, particularly preferably from 0.1 to 1μm.

The mean particle size (d₅₀ value) is the diameter above and below whichin each case 50 wt. % of the particles lie. It can be determined bymeans of ultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid-Z.and Z. Polymere 250 (1972), 782-796).

The graft base B.2) can comprise composite rubbers of silicone rubberand acrylate rubber, these two types of rubber being present, forexample, in the form of a physical mixture or the silicone rubber andthe acrylate rubber, for example, forming an interpenetrating network asa result of their preparation or, for example, the silicone rubber andthe acrylate rubber forming a graft base that has a core-shellstructure. Preferred graft bases B.2) include composite rubbers of from10 to 70 wt. %, particularly preferably from 20 to 60 wt. %, siliconerubber and from 90 to 30 wt. %, particularly preferably from 80 to 40wt. %, butyl acrylate rubber (the indicated wt. % is here based in eachcase on the graft base B.2).

The silicone-acrylate rubbers are preferably composite rubbers having atleast one graft-active site. The silicone rubber and the acrylate rubberpreferably interpenetrate in the composite rubber so that they cannotsubstantially be separated from one another.

Silicone-acrylate rubbers are known and described, for example, in U.S.Pat. No. 5,807,914, EP 430134 and U.S. Pat. No. 4,888,388.

Silicone rubber components of the silicone-acrylate rubber according toB.2 can preferably be prepared by emulsion polymerisation, in which thesiloxane monomer structural units, crosslinkers or branching agents (IV)and optionally grafting agents (V) can be used.

There can be used as the siloxane monomer structural units, for exampleand preferably, dimethylsiloxane or cyclic organosiloxanes having atleast 3 ring members, preferably from 3 to 6 ring members, such as, forexample and preferably, hexamethylcyclotrisiloxane,octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,dodecamethylcyclohexasiloxane, trimethyl-triphenyl-cyclotrisiloxane,tetramethyl-tetraphenyl-cyclotetrasiloxane,octaphenylcyclotetrasiloxane.

The organosiloxane monomers can be used on their own and/or in the formof mixtures of 2 or more monomers. The silicone rubber preferablycontains not less than 50 wt. % and particularly preferably not lessthan 60 wt. % organosiloxane, based on the total weight of the siliconerubber component.

As crosslinkers or branching agents (IV) there can be preferably usedsilane-based crosslinkers having a functionality of 3 or 4, particularlypreferably 4. Preferred examples which may be mentioned include:trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane,tetraethoxysilane, tetra-n-propoxysilane and tetrabutoxysilane. Thecrosslinker can be used on its own and/or in a mixture of two or more.Tetraethoxysilane is particularly preferred in some cases.

A crosslinker can be used, for example, in an amount in the range from0.1 to 40 wt. %, based on the total weight of the silicone rubbercomponent. The amount of crosslinker is preferably so chosen that thedegree of swelling of the silicone rubber, measured in toluene, is from3 to 30, preferably from 3 to 25 and particularly preferably from 3 to15. The degree of swelling is defined as the weight ratio of the amountof toluene absorbed by the silicone rubber when it is saturated withtoluene at 25° C. and the amount of silicone rubber in the dry state.The determination of the degree of swelling is described in detail in EP249964, which is incorporated herein by reference.

Tetrafunctional branching agents are often preferred to trifunctionalbranching agents because the degree of swelling can then more easily becontrolled within the above-described limits.

Suitable grafting agents (V) are compounds that are capable of formingstructures of the following formulae:CH₂═C(R²)—COO—(CH₂)_(p)—SiR¹ _(n)O_(3-n)/2)  (V-1)CH₂═CH—SiR¹ _(n)O_((3-n)/2)  (V-2) orHS—(CH₂)_(p)—SiR¹ _(n)O_((3-n)/2)  (V-3),whereinR¹ represents C₁-C₄-alkyl, preferably methyl, ethyl or propyl, orphenyl,R² represents hydrogen or methyl,n denotes 0, 1 or 2 andp denotes an integer from 1 to 6.

Acryloyl- or methacryloyl-oxysilanes are particularly suitable forforming the above-mentioned structure (V-1) and have a high graftingefficiency. Effective formation of the graft chains is thereby oftenensured, and the impact strength of the resulting resin composition isaccordingly typically promoted. Preferred examples which may bementioned include: β-methacryloyloxy-ethyldimethoxymethyl-silane,γ-methacryloyloxy-propylmeth-oxydimethyl-silane,γ-methacryloyloxy-propyldimethoxymethyl-silane,γ-methacryloyloxy-propyltrimethoxy-silane,γ-methacryloyloxy-propylethoxydiethyl-silane,γ-methacryloyloxy-propyldiethoxymethyl-silane,δ-methacryloyl-oxy-butyldiethoxymethyl-silane or mixtures thereof.

Preferably from 0 to 20 wt. % of a suitable grafting agent, based on thetotal weight of the silicone rubber, is used.

The silicone rubber can be prepared by any method such as emulsionpolymerisation, as described, for example, in U.S. Pat. No. 2,891,920and U.S. Pat. No. 3,294,725. The silicone rubber is thereby obtained inthe form of an aqueous latex. To that end, a mixture containingorganosiloxane, crosslinker and optionally grafting agent is mixed withwater, with shearing, for example by means of a homogeniser, in thepresence of an emulsifier based, in a preferred embodiment, on sulfonicacid, such as, for example, alkylbenzenesulfonic acid or alkylsulfonicacid, the mixture polymerising completely to give the silicone rubberlatex. An alkylbenzenesulfonic acid is particularly suitable because itacts not only as an emulsifier but also as a polymerisation initiator.In this case, a combination of the sulfonic acid with a metal salt of analkylbenzenesulfonic acid or with a metal salt of an alkylsulfonic acidis advantageous because the polymer is thereby stabilised during thesubsequent graft polymerisation.

After the polymerisation, the reaction is ended by neutralising thereaction mixture by adding an aqueous alkaline solution, for example byadding an aqueous sodium hydroxide, potassium hydroxide or sodiumcarbonate solution.

Suitable polyalkyl (meth)acrylate rubber components of thesilicone-acrylate rubbers according to B.2 can be prepared, for example,from methacrylic acid alkyl esters and/or acrylic acid alkyl esters, acrosslinker (VI) and a grafting agent (VII). Examples of preferredmethacrylic acid alkyl esters and/or acrylic acid alkyl esters includethe C₁- to C₈-alkyl esters, for example methyl, ethyl, n-butyl,tert-butyl, n-propyl, n-hexyl, n-octyl, n-lauryl and 2-ethylhexylesters; haloalkyl esters, preferably halo-C₁-C₈-alkyl esters, such aschloroethyl acrylate, and mixtures of these monomers. n-Butyl acrylateis particularly preferred.

As crosslinkers (VI) for the polyalkyl (meth)acrylate rubber componentof the silicone-acrylate rubber there can be used monomers having morethan one polymerisable double bond. Preferred examples of crosslinkingmonomers include esters of unsaturated monocarboxylic acids having from3 to 8 carbon atoms and unsaturated monohydric alcohols having from 3 to12 carbon atoms, or saturated polyols having from 2 to 4 OH groups andfrom 2 to 20 carbon atoms, such as ethylene glycol dimethacrylate,propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate and1,4-butylene glycol dimethacrylate. The crosslinkers can be used ontheir own or in mixtures of at least two crosslinkers.

Examples of preferred grafting agents (VII) include allyl methacrylate,triallyl cyanurate, triallyl isocyanurate or mixtures thereof. Allylmethacrylate can also be used as crosslinker (VI). The grafting agentscan be used on their own and/or in mixtures of at least two graftingagents.

The amount of crosslinker (VI) and grafting agent (VII) isadvantageously from 0.1 to 20 wt. %, based on the total weight of thepolyalkyl (meth)acrylate rubber component of the silicone-acrylaterubber.

The silicone-acrylate rubber can be prepared, for example, by firstpreparing the silicone rubber according to B.2.1 in the form of anaqueous latex. The latex is then enriched with the methacrylic acidalkyl esters and/or acrylic acid alkyl esters that are to be used, thecrosslinker (VI) and the grafting agent (VII), and a polymerisation iscarried out. Preference is given to an emulsion polymerisation initiatedby radicals, for example by a peroxide, an azo or a redox initiator.Particular preference is given to the use of a redox initiator system,especially of a sulfoxylate initiator system prepared by combination ofiron sulfate, disodium ethylenediaminetetraacetate, rongalite andhydroperoxide.

The grafting agent (V) that is used in the preparation of the siliconerubber preferably has the effect of bonding the polyalkyl (meth)acrylaterubber component covalently to the silicone rubber component. In thepolymerisation, the two rubber components interpenetrate and thus formthe composite rubber, which can no longer be separated into itsconstituents of silicone rubber component and polyalkyl (meth)acrylaterubber component after the polymerisation.

For the preparation of the silicone-acrylate graft polymers B mentionedas component B), the monomers B.1 can be grafted on to the rubber baseB.2.

The polymerisation methods described, for example, in EP 249964, EP430134 and U.S. Pat. No. 488,388 can be used thereby.

For example, the graft polymerisation can advantageously be carried outaccording to the following polymerisation method: In a single- ormulti-stage emulsion polymerisation initiated by radicals, the desiredvinyl monomers B.1 are polymerised on to the graft base, which ispresent in the form of an aqueous latex. The grafting efficiency shouldthereby be as high as possible and is preferably greater than or equalto 10%. The grafting efficiency is significantly dependent on thegrafting agent (V) or (VII) that is used. After the polymerisation tothe silicone (acrylate) graft rubber, the aqueous latex is added to hotwater, in which metal salts, such as, for example, calcium chloride ormagnesium sulfate, have previously been dissolved. The silicone(acrylate) graft rubber thereby coagulates and can subsequently beseparated.

Component C

Suitable as the vinyl (co)polymers C include polymers of at least onemonomer selected from the group of the vinyl aromatic compounds, vinylcyanides (unsaturated nitriles), (meth)acrylic acid (C₁-C₈-alkyl esters,unsaturated carboxylic acids as well as derivatives (such as anhydridesand imides) of unsaturated carboxylic acids. Particularly suitable are(co)polymers of

C.1 from 50 to 99 parts by weight, preferably from 60 to 80 parts byweight, in particular from 72 to 78 parts by weight (based on componentC) of vinyl aromatic compounds and/or vinyl aromatic compoundssubstituted on the ring, such as styrene, α-methylstyrene,p-methylstyrene, p-chlorostyrene, and/or (meth)acrylic acid (C₁-C₈-alkylesters, such as methyl methacrylate, ethyl methacrylate, andC.2 from 1 to 50 parts by weight, preferably from 20 to 40 parts byweight, in particular from 22 to 28 parts by weight (based on componentC) of vinyl cyanides (unsaturated nitriles), such as acrylonitrile andmethacrylonitrile, and/or (meth)acrylic acid (C₁-C₈)-alkyl esters, suchas methyl methacrylate, n-butyl acrylate, tert-butyl acrylate, and/orunsaturated carboxylic acids, such as maleic acid, and/or derivatives,such as anhydrides and imides, of unsaturated carboxylic acids, forexample maleic anhydride and N-phenylmaleimide.

The vinyl (co)polymers C are generally resin-like, thermoplastic andrubber-free. Particularly preferred as component C is polymethylmethacrylate (PMMA) or a vinyl copolymer containing at least 70 parts byweight (based on component C) of methyl methacrylate and up to 30 partsby weight (based on component C) of at least one comonomer selected fromthe group styrene, n-butyl acrylate, tert-butyl acrylate and ethylacrylate. A preferred vinyl copolymer C is also a copolymer of C.1styrene and C.2 acrylonitrile.

The (co)polymers according to C are known and can be prepared, forexample, by radical polymerisation, in particular by emulsion,suspension, solution or mass polymerisation. The (co)polymers preferablyhave mean molecular weights Mw (weight average, determined by lightscattering or sedimentation) of from 15,000 to 200,000.

Component D

The composition can optionally comprise one or more further commerciallyavailable polymer additives such as flameproofing agents, flameproofingsynergists, antidripping agents (for example compounds of the substanceclasses of the fluorinated polyolefins, of the silicones as well asaramid fibres), lubricants and mould release agents (for examplepentaerythritol tetrastearate), nucleating agents, stabilisers,antistatics (for example conductive blacks, carbon fibres, carbonnanotubes as well as organic antistatics such as polyalkylene ethers,alkylsulfonates or polyamide-containing polymers), as well as colouringsand pigments, in amounts such that they do not impair the mechanicalproperties of the composition to the extent that the target propertyprofile (no splintering fracture at −10° C.) is no longer fulfilled.

There can be used as flameproofing agents, preferablyphosphorus-containing flameproofing agents, in particular selected fromthe groups of the monomeric and oligomeric phosphoric and phosphonicacid esters, phosphonate amines and phosphazenes. It is also possiblefor a mixture of a plurality of components selected from one or more ofthese groups to be used as flameproofing agents. It is also possible touse other, preferably halogen-free phosphorus compounds that are notmentioned specifically here, on their own or in arbitrary combinationwith other, preferably halogen-free phosphorus compounds. Suitablephosphorus compounds include, for example: tributyl phosphate, triphenylphosphate, tricresyl phosphate, diphenylcresyl phosphate, diphenyloctylphosphate, diphenyl-2-ethylcresyl phosphate, tri-(isopropylphenyl)phosphate, resorcinol-bridged di- and oligo-phosphate, and bisphenolA-bridged di- and oligo-phosphate. The use of oligomeric phosphoric acidesters derived from bisphenol A is particularly preferred. Phosphoruscompounds that are suitable as flameproofing agents are known (see e.g.EP-A 0 363 608, EP-A 0 640 655) or can be prepared by known methods inan analogous manner (e.g. Ullmanns Enzyklopädie der technischen Chemie,Vol. 18, p. 301 ff 1979; Houben-Weyl, Methoden der organischen Chemie,Vol. 12/1, p. 43; Beilstein Vol. 6, p. 177).

Preparation of the Moulding Compositions and Moulded Bodies

The thermoplastic moulding compositions according to the invention canbe prepared, for example, by mixing the constituents in a known mannerand melt compounding and melt extruding the mixture at temperatures offrom 200° C. to 340° C., preferably from 240 to 300° C., in conventionaldevices such as internal kneaders, extruders and twin-shaft screws.

Mixing of the individual constituents can be carried out, in knownmanner, either in succession or simultaneously, either at about 20° C.(room temperature) or at a higher temperature.

The present invention also provides a process for the preparation of themoulding compositions and the use of the moulding compositions in theproduction of moulded bodies.

The moulding compositions according to the present invention can beused, for example, in the production of moulded bodies of any kind.These can be produced, for example, by injection moulding, extrusion andblow moulding processes. A further form of processing is the productionof moulded bodies by deep-drawing from previously produced sheets orfilms.

Examples of such moulded bodies include films, profiles, casing parts ofany kind, for example for domestic appliances such as juice extractors,coffee makers, mixers; for office equipment such as monitors, flatscreens, notebooks, printers, copiers; sheets, tubes, conduits forelectrical installations, windows, doors and further profiles for theconstruction sector (interior fitting and external applications) as wellas parts for electronics and electrical engineering, such as switches,plugs and sockets, as well as bodywork and interior components forcommercial vehicles, in particular for the automotive sector.

The moulding compositions according to the invention can also be used,for example, in the production one or more of the following mouldedbodies or mouldings: Parts for the interior finishing of railwayvehicles, ships, aircraft, buses and other motor vehicles, casings forelectrical devices containing small transformers, casings for devicesfor disseminating and transmitting information, casings and coveringsfor medical devices, massage devices and casings therefor, toy vehiclesfor children, prefabricated wall panels, casings for security devices,heat-insulated transport containers, mouldings for sanitary and bathroomfittings, cover grids for ventilator openings, and casings for gardenequipment. Other moulded bodies and/or mouldings are also contemplated.

The moulding compositions according to the present invention areparticularly suitable for the production of (unlacquered) automotiveinterior components and bodywork parts which must withstand the effectsof light, heat and optionally weathering.

The examples which follow serve to explain the invention further.

EXAMPLES Component A1

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight Mw of 25,000 g/mol (determined by GPC).

Component B1

Graft polymer consisting of 28 wt. % styrene-acrylonitrile copolymer asshell with a ratio of styrene to acrylonitrile of 71:29 on 72 wt. % of agraft base as core consisting of 46 wt. % silicone rubber and 54 wt. %butyl acrylate rubber, prepared by emulsion polymerisation.

Component B2 (Comparison)

Graft polymer consisting of 40 wt. % styrene-acrylonitrile copolymerwith a ratio of styrene to acrylonitrile of 72:28 wt. % as shell on 60wt. % of a particulate graft base as core consisting of purepolybutadiene rubber, prepared by emulsion polymerisation.

Component B3 (Comparison)

Graft polymer consisting of 39 wt. % styrene-acrylonitrile copolymer asshell on 61 wt. % of a graft base as core consisting of butyl acrylaterubber, prepared by emulsion polymerisation.

Component B4 (Comparison)

Graft polymer consisting of 40 wt. % styrene-acrylonitrile copolymerwith a ratio of styrene to acrylonitrile of 76:24 as shell on 60 wt. %of a silicone rubber graft base as core, prepared by emulsionpolymerisation.

Component C

Styrene/acrylonitrile copolymer having a styrene/acrylonitrile weightratio of 76:24 wt. % and a mean molecular weight Mw of 100,000 g/mol(measured by GPC in dimethylformamide at 20° C.).

Component D

D1: pentaerythritol tetrastearate as lubricant/mould release agent

D2: heat stabiliser, Irganox® B 900, Ciba Speciality Chemicals

D3: UV stabiliser Tinuvin 329, Ciba Speciality Chemicals

D4: Black Pearls 800, Cabot Europa G.I.E., Suresnes, France.

Preparation and Testing of the Moulding Compositions

The substances listed in Table 1 are compounded at a speed of 225 rpmand with a throughput of 20 kg/h, at a melt temperature of 260° C. andwith a degassing vacuum of 100 mbar, on a twin-screw extruder (ZSK-25)(Werner and Pfleiderer) and then granulated. The finished granules areprocessed on an injection-moulding machine to the corresponding testspecimens (melt temperature 260° C., tool temperature 80° C.).

The following methods are used to characterise the properties of thetest specimens:

The behaviour in the multiaxial penetration test is used as the measurefor the low-temperature ductility in the crash test with practicalrelevance. The penetration test is carried out in accordance with ISO6603-2 at a temperature of −10° C. on test specimens of dimensions 60mm×60 mm×2 mm. In this test, the maximum energy absorption is determinedon the one hand, and on the other hand in particular the fracturepatterns of a total of ten test specimens are assessed as to whethersplinter-free behaviour occurs in the large majority (at least 90%) ofthe tests, that is to say in at least 9 out of 10 experiments.

The Vicat B120 value, measured in accordance with ISO 306 on testspecimens of dimensions 80 mm×10 mm×4 mm, is used as the measure for theheat distortion resistance.

The melt viscosity at 260° C. and with a shear rate of 1000 s⁻¹,measured in accordance with ISO 11443, is used as the measure for themelt flowability.

The L value, measured in reflection on compositions comprising 0.75 partby weight of carbon black in accordance with DIN 6174, is used as themeasure of the dyeability.

TABLE 1 Compositions and their properties Composition 1 4 5 6 7 8 [partsby weight] (comp.) 2 3 (comp.) (comp.) (comp.) (comp.) (comp.) A-1 75 7575 75 75 75 75 75 B-1 4 7 9 12 B-2 7 B-3 7 3.5 B-4 7 3.5 C-1 21 18 16 1318 18 18 18 D-1 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 D-2 0.1 0.1 0.10.1 0.1 0.1 0.1 0.1 D-3 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 D-4 0.75 0.750.75 0.75 0.75 0.75 0.75 0.75 Weight ratio of B:C 1:5.25 1:2.57 1:1.781:1.08 1:2.57 1:2.57 1:2.57 1:2.57 Double-bond-free rubber yes yes yesyes no yes yes yes Properties Splintering fracture behaviour at yes nono no no yes no yes −10° C. Energy absorption at −10° C. [J] 39 42 38 3938 28 41 41 Melt viscosity (260° C./1000 s⁻¹) 214 227 230 260 230 210228 228 [Pas] Vicat B120 [° C.] 132 132 132 132 132 131 132 132Reflection L 28.6 29.8 29.8 30.3 27.9 27.4 31.6 29.2

The examples in Table 1 show that the advantages in terms of propertiesaccording to the object of this invention are achieved only with thosecompositions in which the graft polymer B and the vinyl (co)polymer Care present in the ratio specified according to the invention and inwhich there is used as the graft polymer B a graft polymer based on asilicone-acrylate composite rubber as graft base (see Examples 2 and 3according to the invention). If the permitted content of the graftpolymer B is exceeded, moulding compositions having poor dyeability anda high melt viscosity, that is to say unsatisfactory processingbehaviour, are obtained (Comparison Example 4). If too little graftpolymer B is used, inadequate multiaxial low-temperature ductility isobtained (Comparison Example 1).

When graft polymer based on pure acrylate rubber is used, inadequatemultiaxial low-temperature ductility is likewise obtained (ComparisonExample 6). The use of graft polymer based on pure silicone rubberresults in unsatisfactory dyeability (Comparison Example 7). If amixture of two graft polymers based on a) pure acrylate rubber and b)pure silicone rubber is used, inadequate multiaxial low-temperatureductility is again obtained (Comparison Example 8). Although the use ofgraft polymers based on butadiene rubber yields good ductility,flowability and dyeability (Comparison Example 5), the aging resistanceof such compositions to the effects of heat, light and weathering isnaturally unsatisfactory for many applications because the rubber baseis sensitive to oxidation because it is unsaturated.

Additional advantages, features and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details, and representativedevices, shown and described herein. Accordingly, various modificationsmay be made without departing from the spirit or scope of the generalinventive concept as defined by the appended claims and theirequivalents.

All documents referred to herein are specifically incorporated herein byreference in their entireties.

As used herein and in the following claims, articles such as “the”, “a”and “an” can connote the singular or plural.

In the present description and in the following claims, to the extent anumerical value is enumerated, such value is intended to refer to theexact value and values close to that value that would amount to aninsubstantial change from the listed value.

What is claimed is:
 1. A composition consisting of A) from 60 to 86parts by weight, based on the sum of components A+B+C, of an aromaticpolycarbonate and/or an aromatic polyester carbonate, B) from 4 to 12parts by weight, based on the sum of components A+B+C, of a graftpolymer comprising B.1 from 10 to 50 wt. %, based on the graft polymerB, of a shell of at least one vinyl monomer, and B.2 from 90 to 50 wt.%, based on the graft polymer B, of a graft base of a silicone-acrylatecomposite rubber, wherein the silicone-acrylate composite rubbercomprises an interpenetrating network of silicone rubber and acrylaterubber, C) from 10 to 30 parts by weight, based on the sum of componentsA+B+C, of at least one rubber-free vinyl (co)polymer of C.1 from 50 to99 parts by weight, based on component C, of a vinyl aromatic compoundand/or a vinyl aromatic compound substituted on the ring and/or a(meth)acrylic acid (C1-C8)-alkyl ester, and C.2 from 1 to 50 parts byweight, based on component C, of a vinyl cyanide and/or a (meth)acrylicacid (C1-C8)-alkyl ester and/or an unsaturated carboxylic acid and/or ananhydride of an unsaturated carboxylic acid and an imide of anunsaturated carboxylic acid, and D) from 0 to 20 parts by weight, basedon the sum of components A+B+C, of at least one polymer additiveselected from the group consisting of flameproofing agents,flameproofing synergists, antidripping agents, lubricants and mouldrelease agents, nucleating agents, stabilisers, antistatics, colouringsand pigments wherein components B and C are present in a ratio of theparts by weight of B:C in a range from 1:1.3 to 1:3.5, and wherein thecomposition is free of inorganic filler.
 2. A composition according toclaim 1, consisting of A) from 70 to 80 parts by weight, based on thesum of components A+B+C, of an aromatic polycarbonate and/or an aromaticpolyester carbonate, B) from 6 to 10 parts by weight, based on the sumof components A+B+C, of said graft polymer, C) from 14 to 20 parts byweight, based on the sum of components A+B+C, of at least onerubber-free vinyl (co)polymer, and D) from 0.2 to 5 parts by weight,based on the sum of components A+B+C, of at least one polymer additive,wherein components B and C are present in a ratio of the parts by weightof B:C in a range from 1:1.6 to 1:2.7.
 3. A composition according toclaim 1 comprising as the graft base B.2, a composite rubber comprisingfrom 10 to 70 wt. % silicone rubber and from 90 to 30 wt. % butylacrylate rubber, based in each case on the weight of graft base B.2. 4.A composition according to claim 3 comprising as the graft base B.2, acomposite rubber comprising from 20 to 60 wt. % silicone rubber and from80 to 40 wt. % butyl acrylate rubber, based in each case on the weightof graft base B.2.
 5. A composition according to claim 1 comprising ascomponent A, an aromatic polycarbonate and/or aromatic polyestercarbonate having a weight-average molecular weight M_(w), of from 22,000to 32,000 g/mol.
 6. A composition according to claim 1 comprising ascomponent A, an aromatic polycarbonate and/or aromatic polyestercarbonate having a weight-average molecular weight of from 24,000 to28,000 g/mol.
 7. A composition according to claim 1 comprising as thegraft base B.2, a silicone-acrylate composite rubber having at least onegraft-active site, wherein the silicone rubber and the acrylate rubberinterpenetrate in the composite rubber so that said silicone rubber andsaid acrylate rubber cannot substantially be separated from eachanother.
 8. A composition according to claim 1 comprising as the graftshell B.1, a methyl methacrylate and/or a mixture of styrene andacrylonitrile.
 9. A composition according to claim 1 comprising ascomponent C, a copolymer of C.1 styrene and C.2 acrylonitrile.
 10. Acomposition according to claim 1 comprising as component C, polymethylmethacrylate and/or a vinyl copolymer comprising at least 70 parts byweight based on component C, of methyl methacrylate and up to 30 partsby weight based on component C, of at least one comonomer selected fromthe group consisting of styrene, n-butyl acrylate, tert-butyl acrylateand ethyl acrylate.
 11. A moulding comprising a composition according toclaim
 1. 12. A polycarbonate composition according to claim 1, whichdoes not display a splintering fracture in a multiaxial dart-penetrationtest at −10°, has a melt viscosity at 260° C. and a shear rate of 1000s⁻¹ of not more than 250 Pas and exhibits a Vicat B120 heat distortionresistance temperature of at least 125° C.
 13. A method for making acomposition of claim 1 comprising mixing A, B, C and optionally D andmelt extruding the resultant.